Viz, the satirical magazine founded by a teenage DHS clerk in Newcastle, turns 25 this week. A comic that runs cover lines such as 'Win A Three-Minute Trolley Dash Round Carol Vorderman's Knicker Drawer' is unlikely ever to come of age, but the great and the good of British comedy will be at a glamorous London party to mark the anniversary.

The name was chosen because the man who dreamt it up, Chris Donald, printed the first issues using a hastily-assembled printing set made from his Dad's cork tiling, and the letters V, I and Z were the easiest to carve out.

Five years later, Donald sold out to Virgin Books and John Brown became its publisher, taking the magazine with him when he founded his eponymous company the following year. It has subsequently been sold twice and 'made two men, Chris Donald and John Brown, very rich', according to Graham Dury, who has worked at Viz for 21 years and now co-edits the magazine with Simon Thorp.

The birthday celebrations have been overshadowed by the release of a new film based on two of the comic's most famous characters, the Fat Slags, which Dury says is so bad it doesn't deserve to be called a turkey. 'I think the BFI need to come up with a new term. The previous publisher [Donald] sold the rights without telling us. When we found out we hit the roof.

'If you read Chris's autobiography, he's very honest about why he did it - he just got greedy. The next publisher said, "Don't worry, it will probably never get made". We said, "What if it does get made and it's shit?" Well, it has been made and it is shit. I've seen bits but I can't bring myself to watch. We're not really bothered if people see it as long as they know it's got nothing to do with us.'

Viz's other characters, including foul-mouthed TV presenter Roger Mellie, unreconstructed Geordie Sid the Sexist, and surreal football star Billy the Fish captured the anti-PC cultural zeitgeist of the mid-1990s and sales rocketed to 1.2 million. 'We knew that wouldn't last,' says Dury, and they now stand at just under 140,000.

Dennis, one of Britain's biggest publishers, which inherited the magazine last year when it bought James Brown's publishing company I Feel Good (IFG), expects circulation to stabilise and plans to increase the number of subscribers (they have tripled since it bought the title).

At its height, only the Radio Times, TV Times and Reader's Digest outsold Viz, but Dury plays down its cultural impact. 'You don't know what the country would be like if Viz had never existed. But I don't think it's changed the country at all, to be honest. It's fun, you read it and you chuck it away.'

Viz may be disposable, but it sits firmly within a proud tradition of subversive British comedy. 'There are influences,' Dury concedes. 'We all grew up with Monty Python and we loved that, and you watch Carry On films when you're young. It's a British brand of humour that doesn't translate well to the States. I think they are a bit cleverer than us.'

Dury was doing a PhD in genetic engineering at Leicester University when Donald asked him to return to Newcastle to work for the magazine full-time. Dury planned to take a beak from his studies for a few years, never imagining how successful the title would become.

Dury says there is very little proprietorial interference from Dennis. 'We are contracted to produce a comic for them and they aren't able to tell us what to put in it, although obviously it has to be within the laws of the land.'

Previous owners too have adopted an arms-length approach. 'For all John Brown's faults, and Christ knows he had a few, he never poked his nose in. When IFG first took over, it tried to, but very quickly realised it wasn't going to work.' Dury hasn't met his ultimate owner, garrulous billionaire and part-time poet Felix Dennis, although he and his partners Thorp and Davey Jones were invited to one of Dennis's recent read ings ('All three of us were washing our hair that night').

'I'm sure he's a very nice man but I don't think he'll come up here and see us. The trains aren't that good. You can get stuck in York.' Dury claims he and his partners lead a prosaic existence, working Monday to Thursday to produce the comic and letting Dennis worry about the commercial concerns, an arrangement that suits them well.

'We spend very little time on that. Occasionally film crews and reporters come up here to meet us and you can see the disappointment in their faces because they're expecting to find this house of fun with all of us doing zany things and they see three blokes sitting here talking about how to get their kids to school and complaining about the litter on the streets.

'We are very, very dull people. We just come in and spend the day trying to make each other laugh - and go home to put the bins out.'

The Viz Years

1979 Chris Donald founds Viz with a schoolfriend and his 15-year-old brother